The invention relates to an aroma composition in which alpha-acetolactic acid (2-hydroxy-2-methyl-3oxobutanoic acid) and diacetyl (2,3-butanedion) are present and to the preparation and use of such a composition.
It has already been known for some decades to use diacetyl as an additive for, for example, butter substitutes in order to give them a butter-like aroma, with which by "aroma" both the odour and taste impression are meant.
Dutch patent specification 93 517 (Stichting Bedrijven van het Nederlands Instituut voor Zuivelonderzoek) describes a process for aromatizing butter and margarine by incorporating alpha-acetolactic acid in said products, or in the aqueous phase of one or more of the starting materials therefor, before the preparation of these products. In this case an (aqueous) solution of alpha-acetolactic acid in a concentration of 10 g/1 is used as aroma composition. The use of a liquid, particularly aqueous, aroma composition containing alpha-acetolactic acid has the drawback that alpha-acetolactic acid is rather unstable. Moreover, liquid aroma compositions make greater demands on the packaging material, and liquid aroma compositions are not suitable for incorporation in dry, powdery products such as flour, cake mixes, etc. in connection with, for example, the formation of lumps.
It should be observed that the process according to the above-mentioned patent specification is directed to the aromatizing of butter and margarine by converting the added alpha-acetolactic acid into diacetyl as much as possible during the preparation thereof. Moreover, by the time such products are sold to consumers, most of the alpha-acetolactate will have been converted into diacetyl owing to the low stability in water of the former compound.
Because diacetyl is a very volatile compound, during storage of such a product diacetyl will gradually escape from the product and consequently the active concentration of diacetyl present in the product will decrease. The high volatile of diacetyl is also the cause of all the diacetyl present already being released at the beginning of the frying process, when frying with a butter or margarine prepared according to the process of the above-mentioned patent specification.
If, moreover, as a result of the limited stability of alpha-acetolactic acid, when incorporated in a liquid, only very little alpha-acetolactic acid is present, only very little alpha-acetolactic acid will be able to be converted into diacetyl, so that the fried product does not obtain a fully butter-like aroma.